Operational Substrate Architecture for Bidirectional Cognitive Continuity: A Multi-Modal Personal-Scale Implementation Layer

This deposit anchors the operational substrate layer for a single-subject n=1 methodological program documenting an architectural specification for multi-modal personal-scale knowledge-graph construction with subject-authored semantic anchoring. The substrate addresses four properties in combination: (i) ingestion of multi-modal personal data streams including visual, audio, biometric, and physiological-sensor signals, with provisions for prospective non-invasive neural-signal integration; (ii) semantic anchoring through a bidirectional methodology in which the subject authors the term ontology and validates each anchor through both forward and backward probing; (iii) local hardware sovereignty in which all raw modality data and all embedding operations remain on infrastructure under direct physical control of the subject, with encryption at rest and optional air-gap provisions for the most sensitive streams; (iv) longitudinal lifetime-horizon design with explicit substrate-distribution provisions across heterogeneous storage substrates for persistence beyond the immediate compute infrastructure. The substrate operates downstream from a methodology layer documented in a separate restricted deposit (DOI 10.5281/zenodo.20309991, published 20 May 2026), which formalizes the bidirectional lexical sondierung methodology applied here to non-textual modalities. Differentiation against adjacent prior and contemporary work documented in this deposit (including the Gordon Bell MyLifeBits archive, the Cathal Gurrin continuously-accumulated personal lifelog, the LifeGraph knowledge-graph series, recent neuro-symbolic personal-knowledge-graph framework proposals, the personal-health-knowledge-graph academic thread, and adjacent consumer-product and quantified-self practitioner landscapes) is framed conservatively: each of the four constituent properties has predecessor work; the combination of all four in a single subject-authored program operated on locally-sovereign infrastructure is, to the verified knowledge of a May 2026 survey, not documented in publicly identifiable adjacent work. Access to the deposit files is restricted; the metadata is publicly accessible to establish a defensive priority anchor over the architectural specification.